Terra Nova Financial
Terra Nova Financial -- a Chicago brokerage that trades for $0.60/share on the OTCBB -- is coming out swinging against a report that it caused Thursday's big crash.

Earlier, TheStreet.com's Michael Baron had identified it as one of the culprits, and it brought to light the fact that Terra Nova has been under a cloud relating to similar claims of naked short selling, and allowance of a high-volume of erroneous trades.

Terra Nova Financial Group, Inc., the parent company of Terra Nova Financial, LLC, a self clearing brokerage firm, today strongly refuted an unfounded report published in TheStreet.com that suggested the unusual trading activity on May 6, 2010 in Procter & Gamble ("PG") originated from Terra Nova. In response to this unsubstantiated report, Terra Nova has thoroughly reviewed its records and determined that on May 6, 2010 Terra Nova cleared a nominal amount of shares (approximately 220,000) of the days activity in PG shares and that those shares traded at or above $60 per share, and there was no additional unusual order or clearing activity. Of that total, Terra Nova executed trades for 1,050 shares of PG at or above $60 per share. Terra Nova did not execute or clear any trades of PG below $60 per share that day. Based on this investigation, Terra Nova is not aware of any link between Terra Nova and the unusual trading activity and wide market price changes in the PG stock.

So that's their stance. It shouldn't be too hard for a third party to either refute or confirm the firm's claims.